1. Introduktion
The Extech LT40 is a compact and accurate LED Light Meter designed for measuring light levels from white LED light sources, as well as standard light sources. This device is essential for professionals needing to monitor and optimize environmental light levels in various settings such as offices, warehouses, public lots, hallways, and stairways. It provides measurements in both Lux and Foot-Candle (FC) units.

Figure 1: Extech LT40 LED Light Meter
2. Sikkerhedsoplysninger
Please read all safety information before operating the Extech LT40 LED Light Meter. Failure to follow these instructions may result in damage to the device or personal injury.
- Do not expose the meter to extreme temperatures or high humidity.
- Avoid dropping the meter or subjecting it to severe impact.
- Keep the sensor clean and free from obstructions to ensure accurate readings.
- Do not attempt to open the meter casing; der er ingen dele indeni, som kan serviceres af brugeren.
- Bortskaf batterier i henhold til lokale regler.
3. Produktet er slutview
3.1 Nøglefunktioner
- USB interface for easy setup and data download.
- Valgbare data sampling rates from 1 second to 24 hours.
- LCD displays current readings, min/max, and alarm status.
- Includes Windows 2000, XP, and Vista compatible analysis software.
- Measures white LED and standard lighting in Lux or Foot-Candle (FC) units.
- Features cosine and color corrected sensor for accurate measurements.
3.2 Komponenter
The Extech LT40 LED Light Meter consists of the following main components:
- Lyssensor: Located at the top of the meter, responsible for detecting light.
- LCD-skærm: Viser måleaflæsninger, enheder og statusindikatorer.
- Kontrolknapper:
- Power knap: Tænder/slukker måleren.
- LUX/FC knap: Toggles between Lux and Foot-Candle units.
- CAL/ZERO Button: Used for calibration and zeroing the sensor.
- MAX/MIN knap: Displays maximum and minimum recorded readings.
- HOLD knap: Fryser den aktuelle aflæsning på displayet.
- Batterirum: Placeret på bagsiden af enheden.
- USB-port: Til tilslutning til en computer for dataoverførsel.
4. Opsætning
4.1 Batteriinstallation
- Locate the battery compartment on the back of the LT40 meter.
- Skub batteridækslet åbent.
- Insert two (2) AAA batteries, ensuring correct polarity (+/-). The batteries are included with the meter.
- Luk batteridækslet forsvarligt.
4.2 Softwareinstallation
The LT40 includes analysis software compatible with Windows 2000, XP, and Vista. Refer to the software's installation guide for detailed instructions on installing and configuring the software for data download and analysis.
5. Betjeningsvejledning
5.1 Tage en måling
- Tryk på Magt knappen for at tænde måleren.
- Select the desired unit (Lux or FC) by pressing the LUX/FC knap.
- Place the light sensor in the area where you wish to measure the light level. Ensure the sensor is facing the light source directly for accurate readings.
- Read the light level displayed on the LCD.

Figure 2: Measuring light levels with the Extech LT40
5.2 Zeroing the Meter
To ensure accuracy, it is recommended to zero the meter before taking measurements, especially in low light conditions.
- Place the protective cap over the light sensor to block all light.
- Tryk på CAL/ZERO button. The display should show '0' or a very low value.
- Remove the cap to begin measurements.
5.3 Using MAX/MIN and HOLD Functions
- MAX / MIN: Tryk på MAX/MIN button to cycle through the maximum, minimum, and current readings. This is useful for monitoring light level fluctuations over time.
- HOLDE: Tryk på HOLDE knappen for at fryse den aktuelle aflæsning på displayet. Tryk på den igen for at slippe holdeknappen og genoptage livemålinger.
5.4 Datalogning og -overførsel
The LT40 supports data logging with selectable sampling rates. Connect the meter to a computer using the USB interface and utilize the included software to configure logging parameters, download recorded data, and perform analysis.
Video: Overståetview of Extech LED Light Meters, including the LT40, demonstrating measurement capabilities and features like Lux/FC units and cosine/color corrected measurements.
6. Vedligeholdelse
Proper maintenance ensures the longevity and accuracy of your Extech LT40 LED Light Meter.
- Rensning: Wipe the meter clean with a dry, soft cloth. Do not use abrasive cleaners or solvents. Ensure the light sensor is free of dust and debris.
- Opbevaring: Når måleren ikke er i brug i længere perioder, skal batterierne fjernes for at forhindre lækage. Opbevar den et køligt og tørt sted, væk fra direkte sollys og ekstreme temperaturer.
- Kalibrering: While the meter is designed for high accuracy, periodic professional calibration may be required depending on your application and industry standards. Refer to Extech's official support for calibration services.
7. Fejlfinding
| Problem | Mulig årsag | Løsning |
|---|---|---|
| Måleren tænder ikke. | Døde eller forkert installerede batterier. | Kontroller batteripolariteten. Udskift batterierne med nye AAA-batterier. |
| Upræcise aflæsninger. | Dirty sensor, incorrect zeroing, or sensor obstruction. | Clean the sensor. Perform a zero calibration. Ensure nothing is blocking the sensor. |
| Displayet viser "OL" (Overbelastning). | Light intensity exceeds the meter's measurement range. | Move the meter to an area with lower light intensity or use a different meter if the light source is too strong. |
| Cannot connect to PC via USB. | Driver issues, incorrect cable, or software problem. | Ensure USB cable is properly connected. Reinstall the analysis software and drivers. Check PC's device manager. |
8. Specifikationer
| Specifikation | Detalje |
|---|---|
| Mærke | Extech |
| Modelnummer | LT40 |
| Produktdimensioner | 5.3 x 1.9 x 0.2 tommer |
| Varens vægt | 4.94 ounce |
| Batterier | 2 AAA batterier (medfølger) |
| Display Type | Digital LCD |
| Forbindelsesteknologi | USB |
| Speciel funktion | Høj nøjagtighed |
| Inkluderede komponenter | Extech LT40 LED Light Meter |
| Oprindelsesland | Taiwan |
| Materiale | Plast |
| Specifikation Met | CE |
9. Garanti og support
Extech Instruments is a trusted brand by professionals, sold in over 100 countries for over 45 years.
- Fabrikant: Extech
- Garanti: Se producentens officielle website or the documentation included with your product for specific warranty details and terms.
- Brugermanual (PDF): For a downloadable PDF version of the user manual, please visit the official Extech website or access it via this link: Extech LT40 User Manual PDF.
- Online support: For additional support, FAQs, and product information, visit the official Extech store: Extech Store on Amazon.





